Lens-block.



W. W. ESSICK.

LENS mock.

APPLICATION FILED NOV. 20, 1916.

1,268,556, Patented Jl mu 4, 1918.

IINITE STATES ra rnn'r m sv LnNs-BLooK.

specificationof Letters Patent.

" Patented June 4, 191a.

Continuatio ofapplication Serial No.186,182, filed March 23, 1916; This application filed November 20,

T1916. Serial Nmisases.

p To fill whom it may concern:

Beit known that I, WILLIAM EssioK, a citizen of the United. Statesyresiding at Reading, in the county of Berks and State of Pennsylvania, have invented certain new, and useful Improvements in Lens-Blocks, of which the following is'a specification.

This invention relates to improvements in the. art of mounting lens blanks. on lensblocks'for surface grinding, and'the object in the present instance is to provide means for accurately. and rapidly placing the blanks on the lens-block.

The present invention is intended as'an improvement on that particular feature de scribed in Letters Patent No. 1143895, issued to me under date of-June 22, 1915, in which I make provision for placing the blanks on the facets, andwhich consists in forming a groove in the raised lens holder facet which the operator can readily see in setting'thei' lens and which enables him to accurately and quickly place the latter.

It is evident that with the above method, the degree of accuracy and the speed with which the blanks are placed, depends to a great extent on the skill and carefulness of the operator.

It is my object in the present invention to provide a simple and positive means for accurately and rapidly placing the blanks even though the operator be both unskilled and careless.

My invention consists in providing a lensblock with a series of registration points, so arranged with relation to the facets or spots on which the lens blanks are to be placed, that when a suitable lens blank positioning device is placed in register with one or more of these registration points, the

position of the lens blank with relation to the spot will be easily and accurately determined.

The invention will apply to lens-blocks having plain or smooth surfaces as well as to those having the facets.

In the present instance I have shown the lens-block formed with raised lens-facets, and, in certain relation with each facet I provide one or more registering points, preferably in the form of indentations in the lens-block coating, adapted to receive registering projections on a lens blank positioning device, so that when the said device is thus placed in; register with the block, the

lens blank may be laid onth'e facet and moved forward until its edgecontacts'with the concaved sufaceof the device, which'will bringthe optical center of the lens blank accurately in position over the center of the facet. I It is to be understood thatthis method of blocking lens blanks is applicabletoftliose blanks-which have beenfinished' as totheir outer edges before being"mou'nted on the lens-block for surface grinding, and the economy of this method of accurately positioning them will be appreciated for' the reason that every blank is optical center at the exact centerof the lens, thus overcoming the [necessity of reshaping or reducing the blank i'n-size after grinding, as would be'the 'casewe're the optical center not so located. The great saving in product due to this method of grind ng is also evident.

In the drawing forming a part of this application Figure 1 is a plan view of a portion of a lens-block showing several of the lens-facets and the relative positions of the registering points.

Fig. 2 shows an elevation and Fig. 3 a plan view of a simple form of lens blank positioning device.

Fig. 4 is a sectional view XX of Fig. 1.

The numeral 1 designates the lens-block and 2 the lens holding facets or spots on its surface.

In certain relation with each facet, that is, at a certain distance from the center of each facet, I form one or. more indentations in the surface of the block, as indicated y 3.

These indentations will serve as registering points for any suitable lens positioning device and will positively determine the proper position for placing the lens blanks on the facets or spots.

The numeral 4 designates a preferred form of lens blank positioning device, which consists of a handle member 5, a body por tion 6 and a pair of re 'stering points in the form of projections depending from the under side of the body portion; this body portion is preferably formed with a concaved surface 8 against which the edge of the lens blank is placed in the act of mounting it on the facet.

taken on the line blanks are to be placed.

The reglstering projections 7 are insertedin the indentations 3, and when these points are" in register the-concaved contact surface 8;; of the device will be in proper position relatively to the facet center. llhef lens blank is then placed on the surface of the facet and its edge='is pressed against the concaved surface 8; of the device, which will bringtheoptical center exactly over the center of the facet, a-precletermined result, and itheblanlci'sthen seated securely thereon by pressure, as usual. The device is then moved-to an adjoining facet and the operation repeated, and when the surface of the lens-block iscovered with blanks: they are ready forsurface grinding in the usual manner. v

t It is-evidentthat both accuracy and speed are assured, even though the operator exercise theininimum ofskill and care...

-Ii3'-Wlll beunderstoodthat inasmuch as each facet or spot is accurately'located relative to the focal axis of grinding,'itis oflvital importance that the optical center plurality of indentations registers exactly with-the center of the facet, and to accomplish this-with ease, accuracy and rapidity has been my object in the present invention.

It is evident that a single elongated depression 9 may be provided in thelens block to serve as a. registering point, instead of a as shown in Fig. 1) or that other similar positioning means as between the device. and the facet may be employed without departing from the; spirit of my invention. I v

The lens-bloc-k being a substantially hemispherical rnetal shell provided with; a 0031i ing of pitchin whichlthe facets and the registration points are formed ,When the coatingis placed on the block.; WhatI claim isi-' 1 A lensblock havingfacets and a plurality of contact walls in fixed relation to, each facet, and: a lensblank positioning device having members adapted to seat against said walls and having. a contact surface adapted to engage a lens blank.

In testimony whereof IafliX my signature.

WILLIAM ESSIGK.

Gopiesofthis patent mayibe obtained for fivecents each; lay-addressing the Commissioner of latents.

. Washington, D. G.- 

